The present invention relates generally to communication systems, and more particularly to address management in an Internet Protocol communication network using network address translation for telephone number based services.
In today""s information age, computers and computer peripherals are often interconnected over a communication network. One type of communication network in general use is an Internet Protocol (IP) network. IP is a connectionless network layer protocol that enables packets of information to be transported based upon a source IP address and a destination IP address contained in the packet.
Probably the most well-known IP network is the Internet. However, various other private and public networks also use IP for internetworking. Such private and public networks may connect to the Internet, for example, through a gateway or other such device.
As the use of IP networks continues to grow, more and more IP-based applications are being developed and deployed. In order to take advantage of certain efficiencies of the IP network, traditional telephone number based communication services, such as telephone (voice), facsimile, and paging, will be implemented over IP networks using IP services.
In accordance with one aspect of the invention, a gateway situated between a first network and a second network in an IP communication system enables communication between a first telephone number based device in the first network and a second telephone number based device in the second network by having a first address for the first telephone number based device for use in the first network, allocating a second address for the first telephone number based device for use in the second network, and performing address translation on IP communication messages exchanged between the first telephone number based device and the second telephone number based device such that the first address for the first telephone number based device is used in the first network and the second address for the first telephone number based device is used in the second network. The gateway typically allocates the second address from an address pool including a number of addresses that are available for use in the second network. The gateway typically maintains an address translation entry in an address mapping database mapping the first address for the first telephone number based device to the second address for the first telephone number based device, in which case the gateway uses the address translation entry to perform the address translation.
In accordance with another aspect of the invention, a gateway situated between a first network and a second network in a IP communication system enables communication between a first telephone number based device in the first network and a second telephone number based device in the second network by having a first address for the first telephone number based device for use in the first network, allocating a second address and a port number for the first telephone number based device for use in the second network, and performing address translation on IP communication messages exchanged between the first telephone number based device and the second telephone number based device such that the first address for the first telephone number based device is used in the first network and the second address and port number for the first telephone number based device are used in the second network. The gateway typically allocates the second address from an address pool including a number of addresses that are available for use in the second network. The gateway typically maintains an address translation entry in an address mapping database mapping the first address for the first telephone number based device to the second address/port number pair for the first telephone number based device, in which case the gateway uses the address translation entry to perform the address translation.
In a typical embodiment of the invention, the first network is a private network, and the second network is a public network. The first telephone number based device has a private address for use in the private network. The gateway allocates a public address or public address/port number pair for the first telephone number based device for use in the public network, and performs address translation on IP communication messages exchanged between the first telephone number based device and the second telephone number based device such that the private address for the telephone number based device is used in the private network and the public address or public address/port number pair for the first telephone number based device is used in the public network.
In accordance with another aspect of the invention, a gatekeeper determines a gateway for a called device based upon a telephone number for the called device.
In accordance with another aspect of the invention, a telephone number based device in a first network determines a gateway for communicating with a second telephone number based device in a second network, obtains an address for the second telephone number based device for use in the first network, and establishes a connection to the second telephone number based device through the gateway using the second address for the second telephone number based device.